Rhodora 
JOURNAL OF 
THE NEW ENGLAND BOTANICAL CLUB 
— == 
Vol. 10. August, 1908. No. 116. 
TWO NEW SPECIES OF ACROCHÆTIUM. 
Е. S. COLLINS. 
Acrochetium minimum n. sp. Strato basali e filamentis epi-vel en- 
dophyticis constituto, ad superficiem vel inter cellulas superficiales 
plantz hospitis repentibus, initio liberis, mox plus minus concretis, 
non autem membranam veram formantibus; cellulis 2-4 м diam., 
1-4 diam. longis, forma valde irregularibus; filamentis basalibus 
ramos plures breves emittentibus, ultra superficiem plante hospitis 
emergentes, 1-4 cellulares, cellulis 2-3 м diam., 14-3 diam. longis, 
spe in sporam pyriformem, indivisam, 5 X 7 y, desinentes; minus 
frequenter filamenta longiora, usque ad 25 cellulas, cellulis ad 8 diam. 
longis, 2-3 и diam., simplicia, interdum sporam lateralem, sessilem 
vel ad pedicellum -unicellulare affixam, spore terminali similem, 
gerentia. 
Basal layer composed of epi- or endophytic filaments, creeping 
on the surface or among the superficial cells of the host plant, at first 
free, later more or less united, but not forming a genuine membrane; 
cells 2-4 м diam., 1-4 diam. long, of quite irregular form; basal fila- 
ments emitting many short branches, extending beyond the surface 
of the host, 1-4-celled, cells 2-3 м diam., 14-3 diam. long, often 
terminating in an undivided pyriform spore, 5 X 7 м; less frequently 
emitting longer filaments, up to 25 cells, cells up to 8 diam. long, 
2-3 м diam., occasionally bearing a lateral spore, sessile or on a uni- 
cellular pedicel, similar to the terminal spore. On Desmarestia 
viridis (Fl. Dan.) Lamour., Robinson's Hole, Massachusetts, Aug., 
1907. I. F. Lewis. 
'The dimensions here given are less than those of any hitherto de- 
scribed species of the genus, and the erect part is smaller in propor- 
tion to the horizontal, but it seems to be an Acrochetium. The 
filaments of the basal layer wind about the round cortical cells of the 
Desmarestia, but do not seem to penetrate below the outer layer; the 
cells assume all possible forms, according to the space available for 
